Radiant heating

Someone on the San Miguel listserv just asked about this, just in time for me to obsess (have about three weeks before my tile floors start going in.) I understand from responses there that you can use either copper or what sounded like PVC tubing. Does anyone know of the average cost per square foot or square meter? Also, do you need to have a specialist install it, or can I have my construction/plumbing crew do it? ---------------------------- "The first question I ask myself when something doesn't seem to be beautiful is why do I think it's not beautiful. And very shortly I discover there is no reason." John Cage

Re: [not_ally] Radiant heating

I would think twice before opting for a hot water radiant heating system in Mexico. They are not as simple as they appear to be. It always seems strange to me that laymen with no construction experience will look at a project and conclude, “That’s simple, anyone can do it.” Well anyone can’t do it usually. There is a lot of math and science involved in the building industry. I have never heard of anyone providing a cost per square foot for one of these systems, there are too many variables.I worked for 48 years in the pipe trades. I went through a normal five-year apprenticeship including on the job experience, and classroom work for which college credit was earned. I then worked as a journeyman, foreman, general foreman, project manager, etc. I have been licensed as a plumber, pipe fitter, and refrigeration technician. In most jurisdictions in The US it is illegal for anyone without a license to work for remuneration as a plumber, electrician, etc., exceptions are made for a person working on their own home provided all codes are complied with. The licenses are issued to a tradesman personally after testing and proving qualifications, and must be renewed annually like a drivers license. I also owned my own control company. I am qualified to give some advice on heating systems. I have installed many of them. If you plan to use in floor grids, they can be a specialized type of plastic, but they are usually cooper tubing. The joints in the copper tubing should be either silver soldered (really a form of brazing) the solder contains a high percentage of silver and is fairly expensive, or at least they should be soldered with 95/5 solder (95% tin, 5% antimony), that is the type of solder used in refrigeration systems. Care must be taken to assure that the copper tubes to not contact a dissimilar metal, such as the rebar in the floor, if they do, a condition called electrolysis will be present. Electrolysis will destroy the copper tubing.I think you would be hard pressed to find a tradesman with the education and experience to do the installation in Mexico. Most of the “plumbers” and “electricians” I have talked to in Mexico are simply unqualified. Most of them are simply “handymen”, not qualified tradesmen. I believe the lack of enforced building codes is the reason. There are exceptions of course. I have spoken to a few that were highly qualified, that is not the norm here though A separate, dedicated water heater will be required, a domestic (household) water heater is completely inadequate, and it will never produce the heat required. In this climate, you could probably set the heater to produce 150º F or 160º F, in Alaska we used to set them to produce 190º F in order to heat the building adequately. A pump to circulate the hot water will run every time a thermostat in any zone calls for heat. You could get by with one zone for the whole house, but that would be wasteful. You would probably need at a minimum two zones for a two-story house. More zones than that are recommended for economy and comfort. Installing thermostats will require more wiring in the house of course. There will need to be elaborate controls, to start the pump, and open the valve for the zone or zones calling for heat. The controls are low voltage, so there will need to be a transformer to drop the voltage. The heaters are heavy; the heat exchangers in them are made of cast iron. The heater, (usually called boilers although that is a misnomer), must be installed inside a room with ventilation and exhaust to outside air so the boiler will have adequate combustion air, and to keep all the electrical controls dry. It’s also so you won’t die of carbon monoxide poisoning. These are what are called a “closed system”, that is a system where the water re-circulates and that is not directly connected to the domestic water supply. There is what amounts to check valves to prevent any water from the heating system to back flow in to the household water supply and contaminate it. They use low-pressure water; we usually had to install a pressure-reducing valve to drop the pressure to 15 PSI. Here you would usually have a hard time boosting the pressure to 15 PSI. Since a column of water one foot high produces .433 PSI, the outlet from your tinaco would need to be located 34.56 feet above the inlet of your heater, not the ground level, to consistently produce at least 15 PSI at the heater.In my own opinion, unless a home was designed for this type of heating before it was built, it is not a practicable option here. The cost of electricity and propane must be considered too.Here is a link to another reply I made to a post a couple of years ago to a person that was considering adding this type of heating to an apartment, using baseboard diffusers instead of in floor grids.http://www.mexconnected.com/perl/foros/gforum.cgi?post=18916#18916I don’t mean to be discouraging, but if you are considering this type of a heating system, there are many things to consider. I don’t post to this forum often, it seems there are a lot of well meaning but technologically challenged people that will always post a reply that “My “plumber” says that doesn’t matter.” Everything in this post does matter.Rex"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

Re: [RexC] Radiant heating

I've delt with radiant floor heating and it is definitely a complicated system. The state of the art systems that I have seen come from Europe. They are made of some kind of plastic tubing and after the tubing is attached to the existing concrete floor, a special layer of concrete is put on top of the tubing. Like Rex said, there is a complex system of valves, pumps, manifolds and all put together by people trained in these systems. If I were considering a heating method, I'd think about high effeciency free standing gas heaters that look a lot like wood stoves. You should also think about double pane glass windows and other energy efficient methods of construction to keep the "R" values high which will keep your energy consumption down.

Re: [Esteban] Radiant heating

A word of caution about high efficiency heating systems. The average heater is rated at about 73 % efficiency. Some of the high efficiency models are rated as high as 91-93% efficiency. The high efficiency heaters are what we call “water producing.”They don’t really produce water but they are so efficient at extracting heat, the relative humidity of the combustion air will condense in the flue. The flue will never be hot. If you place your hand on one, it will be room temperature. The condensation will run down the flue, there will be a drain at the bottom of it. Because of the water in the flue, you cannot use a metal flue. Special plastic pipes are used. I don’t remember the name of that plastic right now. It looks something like ABS, shiny black in color, but very thin walled. As with most plastic pipe, when you are gluing it together, you are not really gluing it, you are performing a chemical weld. It takes 24 hours for the joints to set. You must provide temporary support for 100% of the flue pipe until all joints are set. You must then run a tube from the drain at the bottom of the flue to a floor drain. It is illegal to install one of those high efficiency units in most jurisdictions in The US if a floor drain is not available. If you install one of those units with no floor drain, you can put a bucket under the drain, but you better remember to empty the bucket every day. I have installed and maintained some of these units. They are full of high tech temperamental parts. They are a pain in the neck to maintain and get replacement controls for. Even though I know how to fix them, I personally wouldn’t want, or choose to install one for my own home. In spite of the fuel cost savings, they are not worth bothering with as far as I’m concerned.To each his own.Rex"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

Re: [RexC] Radiant heating

I don't think we are talking about the same thing. I'm talking about a simple free standing gas fireplace unit that looks lke an old fashioned wood stove. Nothing fancy; nothing real high tech. Check out this one: http://www.centralfireplace.com/pd-fs-32.html

Re: [Esteban] Radiant heating

Esteban, That looks like good unit. I kind of doubt their claim of “up to” 88% efficiency though, but that would only affect economy of operation, not the heat output. I have checked several similar units online, some of them have higher outputs, but for many areas in Mexico 32,000 BTUs will be adequate to heat one or more rooms, depending on the season.In California we used to never install less than an 80,000 Btu furnace for forced air heat. In Alaska, we never used a unit with less than 150,000 BTUs for forced air heating. Those are minimums, not maximums, for very different climates than we have here.I have checked out several units similar to the one you have recommended. Some of them have higher heat outputs, but of course that means higher fuel usage too. I noticed that a millivolt thermostat is offered as an option. That indicates to me that the unit probably has a thermopile generator on it to power the thermostat. A thermopile is a unit that is mounted so that it is in the pilot light flame. The thermopile is made of two dissimilar metals. The heat from the pilot flame causes electrons from one of the metals to jump to the other. This generates very low millivoltage, which powers the thermostat, and usually the gas control valve. The old, now almost obsolete wall furnaces were all powered that way with no outside source of electricity. It indicates to me that the unit has a standing pilot flame, and not an electronic pilot igniter. That is not so good for fuel economy, but it is good during a power outage, the burner will still ignite with no power. There are a lot of choices out there. Here in Cuernavaca with our mild climate in winter, and in a leased house, a couple of those 1500-watt electric powered oil filled radiators do the trick for us.Rex"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

Re: [RexC] Radiant heating

I totally agree with you Rex. I chose that one website to show what's available. I didn't really look at the details. We never need heating here in Maz. In Washington, we had a free standing gas heater with a piezo ignition. It would lite automatically or manually. The manual operation was good when the electricity went out. I am not familiar with heating needs in the higher elevations in Mexico but one of those freestanding gas fireplaces are sure nice and easy to use. You could chose a low BTU one, look for the greatest efficiency and you'd be off and running. Now if I could just find a cheap way to A/C my bedroom in the Mazatlan summer, I'd be very happy. Any ideas?

Re: [Esteban] Radiant heating

All I have is theory. I did great in General Physics in HS and my BA not BS degree in undergraduate school was physics. I know that one KWH of electricity costs me about 20 cents US (marginal rate here in Ajijic) and that the same energy in gas, 3414 BTUs, costs me about 5.4 cents. (One liter of gas costs me about 37 cents, as I recollect, 1 gallon of gas has 90,000 BTUs)

I purchased a G9 series Unvented Gas log set, a Robert H Peterson Co. REAL FYRE 24 inch unit with a maximum output of 36,000 BTUs and the low setting of 17,000 BTUs So far I only have used the low setting which costs me about 27 cents per hour, and sure puts out a lot more heat than does a small electric heater of about 1350 watts, which would also cost that amount to run per hour.

Trouble is I am not an expert at carbon monoxide poisoning, remember it's an unvented unit. I 'm going back to the states Monday and while there I shall purchase a CO monitor.

I keep one door open a crack while I run the unit. The fire log heats up not only the room but the bricks. I turn the unit off when I go to sleep, and close the door. The bricks say hot and give off heat all night.

Please give me some advise folks. What do you think of those of us who use unvented units? How about some safety suggestions.

Re: [johanson] Radiant heating

Pete, You re doing the right thing to leave the door ajar, and turning off the heater when you go to sleep. Personally, I would never use an un-vented heater. Carbon monoxide is odorless and tasteless. I have suffered CO poisoning twice. Once at work, and once while staying at my brothers house in Chico, California. If you get a lot of it like I did at work, the symptoms are extreme nausea. If you look in a mirror, you will look as red as Bushes’ budget. I was awake when I had the exposure at work and was able to get away from the danger OK.I didn’t have as much exposure at my brothers house. I was staying with him during an illness to help him until he recovered. I was laying on his sofa watching television one evening, when he went out to bring his car in to the garage. I fell asleep on the sofa. I woke up the next morning about 7 AM. When I saw that all the lights were still on, I knew there was something wrong.I had trouble waking up, it took a lot of effort to get up, I knew there was something drastically wrong. I heard something in the garage, and went to check it. I found that my brother had brought the car inside, closed the garage door, and passed out while the car was still running the night before. The forced air furnace was located in the garage, the intake air had been pulling air, and exhaust fumes from the garage in to the house all night. When I realized that the car was still running, I wondered why I didn’t smell any fumes. I realized much later it was because I had been breathing them all night. My brother survived, the point of this post is that carbon monoxide is deadly stuff and you will not smell it. I know. I experienced it, you will not smell it. Every year in cold climates, some people will die of CO poisoning. Last year a man and most of his family died in Anchorage of it. He had blocked the fresh air intake to the space where the forced air furnace was located, to keep cold air out of the house. It is usually small innocuous things like that, that cause these incidents. Not changing the air filters in a forced air system in a timely manner has caused many deaths. If the filters get very dirty and not enough air is passing through them, the heat exchanger will overheat and possibly crack, allowing CO to be spread throughout the house. If that happens at night after everybody is asleep, they will not be able to wake up, they will die. I know from my own experience, It took every bit of strength I could muster to wake up enough to get off that couch at my brothers house. Don’t fool with CO, it will kill you if you give it half a chance. Rex"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

Re: [RexC] Radiant heating

Darn I wrote a response and I guess I accidentally deleted it. Well here goes again. I too am very afraid of Carbon monoxide poisoning. Non vented units be they fire logs or oil heaters are very popular down here in Ajijic. When I ask the users whether or not they vent their homes, they all say no and talk about how their homes are not air tight. That kind of talk scares me, Right now my 17,000 BTU unit is giving off heat, the upstairs door is open a little more than a crack and the house is 69 F while the outside temp is 10 degrees lower.At 11 PM I turn the unit off and close all of the doors. The bricks surrounding the heat source which have been acting as a heat sink will be quite hot. They will continue to give off heat all night still being warm to touch when I get up in the morning. I'm leaving for WA tomorrow and when up north for 16 days, I will pick up a CO monitor with an alarm on it. Thanks for your input.

Re: [johanson] Radiant heating

Rex, would you mind if I posted yours to the SMA coollist where I saw radiant heating addressed? It would be good information for other folks considering this option, I think (certainly made me decide against it.)

Estaban, that was a nice looking stove. Pretty luxe options, though ("I'll take the rustic model with the 24 karat gold door, please")! ---------------------------- "The first question I ask myself when something doesn't seem to be beautiful is why do I think it's not beautiful. And very shortly I discover there is no reason." John Cage

Re: [not_ally] Radiant heating

Thank you all for your knowledgable repartee. In reading elements of this thread I wondered about the risk of not venting a gas heater. Growing up we had unvented gas heaters, but we always turned them off at night.

Now I have a question which does not necessarily apply to Mexico, but probably could. My Mom's 30+ year old house has a piped-in natural gas fireplace set, with the "key" inserted into the brick on the right of the fireplace...turn on the key, and light the fake logs...easy, except when turned on unburned gas leaks out through the key. Dangerous. My Mom and late Dad talked to a plumber and the gas company, and each said it was the realm of the other. Who do I go to to get this fixed? And what is the repair approach? Sorry, but I'm totally lost here. If necessary, I think the gas line is accessable through the exterior brick of the fireplace, but I'm not sure.

Re: [Texwheel] Radiant heating

Tex, The “key” is actually a removable handle for a gas valve, which is in the wall. The valve is obviously leaking in the open position. A gas valve should not have packing in it; they have a “ground fit”, which means that the internal parts are lapped to fit, metal to metal. If a valve with packing in it was improperly installed, it should be replaced with one that meets code requirements. If it is the correct type, then it will need to be re-lapped, or replaced. There is also the slim possibility that the tension nut on the bottom of the valve has become loose due to frequent use of the valve, and subsequent wearing away of the metal. If that is the case, then simply tightening that nut would be the fix. It is the homeowner’s responsibility to maintain it. That means the solution is to hire a different, qualified plumber. If their city, county, and/or or state require licenses for plumbers, ask to see his license(s). No handyman should be entrusted with a job like this, small as it is. They take too many dangerous shortcuts.Rex"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

Re: [Texwheel] Radiant heating

Tex, There are several commercial products available, but the old tried and true method for finding leaks in gas lines is to use soapy water. Mix up some soap and water, then use something like a paintbrush or even an old rag and coat the pipe joints. When you see some bubbles, there’s your leak. A little safer than your Mom’s method : -)Rex"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

Re: [johanson] Radiant heating

Pete, I hope you check this forum while you’re up north. If you are going to buy a CO detector, I recommend that you get one that records the highest CO readings in the past day, as well as displaying the present level. They cost a little more, and are sometimes hard to find, but it is good to know if there was a higher reading during the night while you were asleep. A low reading in the morning is good, but it is reassuring to know that it doesn’t rise to a possibly dangerous level overnight. Rex"The supreme happiness of life is the conviction that we are loved" - Victor Hugo

Re: [RexC] Radiant heating

Thanks Rex for the input. I too hope to find a CO devise that will quantify the actual CO levels, to include the highest level reached. It's really fun seeing the snow up here, only because I know I will be back in Jalisco in 2 weeks.

Re: [not_ally] Radiant heating

Just one more thought. I'm not real technical but I perceive most of the posts are thinking US standards. I have two gas heaters in SMA and consider myself lucky, as many of my friends have no heat at all here. I would kill for nice cozy warm floors. My friend is using one of those instant heat gas hot water heaters and estimates his heating costs will be quite low. Check it out before you lay that tile.